Outdoor theater sound system



April 11, 1961 R. P. HERZFELD OUTDOOR THEATER souun SYSTEM Filed May a, 1957 I -1 PL 2O FIG.

INVENTOR. RICHARD P Hznzrsu:

AT'IZORNEY MTLTLI 1 FIG. 2

United States Patent OUTDOOR THEATER SOUND SYSTEM Richard P. Herzfeld, 3541 North Lake Drive, Milwaukee, Wis.

Filed May 6, 1957, Ser. No. 657,285

2 Claims. (Cl. 250-6) This invention relates to a method and apparatus for distributing sound to automobiles at an outdoor theater.

The usual sound system employed in outdoor theaters is notable primarily for the poor quality of the sound. The small speakers used in a closed wiring circuit are necessarily low cost units since they are subjected to all types of weather with consequent deterioration and also appear to be attractive to the souvenir conscious segment of the populace. The maintenance and replacement costs are high with the usual theater having at least one full-time employee attending the speakers. The primary object of this invention is to improve the sound quality by using the speaker in car radios. This has been suggested before but all suggestions required modification of the cars and this is obviously beyond the control of the theater operator and there are very few patrons who would incur the expense on their own behalf. My system contemplates no change in the automobile itself. The present system is attractive to theater operators since it permits a great reduction in costs while adding to enjoyment of the entertainment.

I propose to transmit the audio portion of the moving picture as a radio signal on a frequency within the standard broadcast band for reception by the individual automobile radios of the patrons. Such transmission can be in the form of a limited area broadcast or by a conductor connected to the antenna ofthe automobile radio (the latter system should be static-free). The drain on the battery can be ofiset by trickle-charging the battery by means of a simple plug-type connection inserted in the cigarette lighter receptacle in the automobile.

Other objects and advantages will be pointed out in, or be apparent from the specification and claims, as will obvious modifications of the two embodiments shown in the drawings, in which:

Fig. l is a partially schematic view of a sound distributing system embodying the present invention'with transmission of the radio signal by a limited area broadcast;

Fig. 2 is a partially schematic view similar to Fig. 1 but showing the transmission of the radio signal by a wire from the transmitter to the radio antenna;

Fig. 3 is a view showing the lead connectors to the antenna and cigarette lighter for receiving the radio signal and charging the battery;

Fig. 4 is a view similar to Fig. 3 but showing a single lead from the post for charging the automobile battery. This is the arrangement utilized in the system shown in Fig. 1; and

Fig. 5 is an enlarged fragmentary view of the post showing the controls for charging the battery.

2,979,607 Patented Apr. 11, 1961 Referring to Fig. l in detail, the audio signal from the sound movie projector is fed into transmitter 12 by wire 14. The transmitter converts the audio signal to a radio frequency signal in the standard broadcast band to be broadcast from antenna 16. The frequency will have to be assigned by the FCC and would be a non-interfering frequency authorized for limited area broadcasting only. The antenna can be conventional or may be the wiring already installed for the former type of sound systems. The radio waves, represented by jagged line 18, are received by the antenna of car 22. This permits the superior speaker of the car radio to be used during the showing of the movie.

Most patrons would be concerned about the drain thus imposed on the car battery (even though this is negligible in the case of the modem 12 volt systems) and to overcome this barrier to acceptance by the public atricklecharge can be made available at post 26 adjacent each car stall. Thus, lead 30 would be connected to the D.C. source (which could be transformed and rectified at the post to permit high voltage A.C. transmission with less power loss) and provided with a plug-in device 32 for insertion in the cigarette lighter receptacle in the car. More details in this connection will appear hereinafter.

In the system of Fig. 2, the radio frequency signal from transmitter 12 is sent over wiring 24 to post 26 and into lead 28 which has a clip or alligator connector 29 for attachment to the car antenna 20. This arrangement eliminates any broadcast through the air and could well eliminate need for an FCC license. The big advantage, however, resides in eliminating static interference with the signal in times of atmospheric disturbance. In this system the wiring formerly used for the speaker leads could be used to carry the signals.

Returning now to the battery charging question, various conditions must be met to adequately cover the situation. Thus, automobiles have both 6 and 12 volt systems and the polarity varies with different makes of cars. To accommodate the various situations, I propose to provide the control box 33 on each post with an On-Otf switch 34, a voltage selector switch 36 (for selecting 6 or 12 volts) and a polarity switch 38 marked and which is selected after referring to the chart 40 as seen in Fig. 5.

To accommodate those patrons whose automobiles have no radio or are defective, a small number of individual loud speakers can be retained at a designated area of the outdoor theater.

In both forms of this invention the sound is broadcast at radio frequency but in one system the radio waves are propagated through the air while in the other system the waves are transmitted by wire directly to the receiving antenna. The latter system avoids static and also avoids the need for an FCC limited area broadcast license.

Although but two embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

I claim:

1. A sound system for an outdoor theater wherein the patrons sit in automobiles having battery powered radios, means including a movie projector to produce an audio signal, a transmitter for converting and broadcasting said 5 signal on a frequency within the standard broadcast range for reception by the automobile radios of the theater References Cited in the file of this patent patrons, and means for charging the several automobile UNITED STATES PATENTS batteries while the signal is bemg received by 531d automobile radian 1,954,931 Hambuechen Apr. 17,1934 2. In an outdoor theater sound system according to 5 2359316 Lyle 1941 claim 1 in which said means for charging the automobile 2' Halstead Sept' 1946 battery includes a source of direct current electricity, a 3] Phyfc May 1949 conductor connected to said source adapted for plug-in Chcmel Sept connection in the cigarette lighter receptacle in the auto $619,544 Samrfield 1952 mobile to connect said conductor into the electrical sys- 10 2765365 Gmsh ct 1956 cm of the automobile to chars: the but; 2,851,537 Rosenberg et a1. Sept. 9, 1958 

